The invention relates to a field device for controlling actuators and for processing and relaying sensor signals, having a control unit for providing control signals, having a transmission device for transmitting the control signals within the field device, wherein the transmission device comprises at least one interface, which is designed for electrical coupling of a function module, having at least one function module designed as an engine control module, which is equipped for controlling at least one electrical drive depending on control signals from the control unit, wherein the control unit and the at least one function module are electrically connected to each other by means of the transmission device.
From the product catalogue “simatic ET 200” from the company Siemens dated April 2005, a field device is known for use in an automation system. This field device is provided for connection to a field bus and has a modular structure such that differently configured interface modules, which are designed for connection with different field bus systems, can be connected to so-called periphery modules. The task of the periphery module is, for example to record and process sensor signals or to control electrical drives. The periphery modules provided for controlling electrical drives are also designated as engine starters and are designed, on the one hand, for a signal-transmitting connection with the interface module and, on the other hand, for a power-transmitting connection with a so-called terminal module, wherein the terminal module is provided for feeding in the electrical energy for the electrical drives to be controlled via a so-called energy bus. Accordingly, two bus systems independent of each other are provided in the known field device, on the one hand, the energy bus for supplying the engine starter and, on the other hand, a signal bus for transmitting electrical signals within the field device.